/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.runtime.state.ttl.mock;

import org.apache.flink.api.common.functions.AggregateFunction;
import org.apache.flink.api.common.state.AggregatingStateDescriptor;
import org.apache.flink.api.common.state.State;
import org.apache.flink.api.common.state.StateDescriptor;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.runtime.state.internal.InternalAggregatingState;

/** In memory mock internal aggregating state. */
class MockInternalAggregatingState<K, N, IN, ACC, OUT>
	extends MockInternalMergingState<K, N, IN, ACC, OUT> implements InternalAggregatingState<K, N, IN, ACC, OUT> {
	private final AggregateFunction<IN, ACC, OUT> aggregateFunction;

	private MockInternalAggregatingState(AggregateFunction<IN, ACC, OUT> aggregateFunction) {
		this.aggregateFunction = aggregateFunction;
	}

	@Override
	public OUT get() {
		return aggregateFunction.getResult(getInternal());
	}

	@Override
	public void add(IN value) {
		updateInternal(aggregateFunction.add(value,  getInternal()));
	}

	@Override
	ACC mergeState(ACC acc, ACC nAcc) {
		return aggregateFunction.merge(acc, nAcc);
	}

	@SuppressWarnings({"unchecked", "unused"})
	static <IN, OUT, N, ACC, S extends State, IS extends S> IS createState(
		TypeSerializer<N> namespaceSerializer,
		StateDescriptor<S, ACC> stateDesc) {
		AggregatingStateDescriptor<IN, ACC, OUT> aggregatingStateDesc =
			(AggregatingStateDescriptor<IN, ACC, OUT>) stateDesc;
		return (IS) new MockInternalAggregatingState<>(aggregatingStateDesc.getAggregateFunction());
	}
}
